Conventional touch-control substrate of a touch screen includes a driving electrode and a sensing electrode, which are crossly configured and electrically insulated from one another. When touched by a human body or a stylus, the electric induction (e.g., capacitance) between these two electrodes in the touch control region may be affected. This affection may be used to determine a touch position. To reduce resistance, the driving and sensing electrodes are made of silver, aluminum, and other metals with a low resistance. However, such metals are not transparent.
Metal mesh is then used for the driving and sensing electrodes to provide desired display effect. For example, as shown in FIG. 1, conductive structures 09 are used for driving electrodes 01 and sensing electrodes 02, and may be mesh-shaped, instead of sheet-shaped. In other words, the driving electrodes 01 and the sensing electrodes 02 may include a metal mesh having metal grids with a number of small holes. Because the metal wires in the metal grids are so thin and often invisible to naked eyes, use of metal mesh will not affect the display effect, while still providing conductive function.
The driving electrodes 01 and the sensing electrodes 02 having the metal mesh are disposed in a same layer level. To avoid conduction at the intersection of these two types of electrodes, the conductive structures 09 of one of the electrode types (for example, the driving electrodes 01) are divided into multiple individual conductive structures. Adjacent individual conductive structures 09 in a single driving electrode are electrically connected to each other through conductive bridges 011 made of ITO. An insulating layer may also be formed between the conductive bridges 011 and the conductive structures 09, while the conductive bridges 011 are electrically connected to the conductive structures 09 through first via-holes 03 formed in the insulating layer.
The touch-control substrate is formed by using a patterning process. Obviously, in the patterning process, satisfactory position relationship between already-formed structure and to-be-formed structure or between the mask and the touch-control substrate must be assured. For this purpose, alignment marks are often marked on the touch-control substrate to adjust the position of the mask with respect to the touch-control substrate. To avoid interfering with display function, such alignment marks are positioned outside of display region.
However, under certain circumstances, such alignment marks have to be positioned within a display region. For example, large size touch-control substrate with multiple regions for separate exposures may have an exposure region disposed entirely inside the display region. In this case, the alignment mark corresponding to this exposure region has to be positioned inside the display region. Although invisible to naked eyes, metal-mesh-shaped conductive structures may still affect position alignment of the mask because such metal-mesh-shaped conductive structures may be detected by alignment equipment.
As shown in FIG. 2, conventional touch-control substrate has a mark region 08 enclosing an alignment mark 081. The mark region 08 does not include any conductive structures. Consequently, due to the absence of conductive structures in the mark region 08, the mark region does not have any touch sensing (or control) function. Touch control effect of the touch screen is adversely affected.
The disclosed touch-control substrates, fabrication methods thereof, and display devices including a touch-control substrate are directed to at least partially alleviate one or more problems set forth above and other problems in the art.